On a Matrix visualization that I created, I have the ability to export the underlying data to Excel. And that works. But it seems to display only some of the columns from the source table - not all. And even that is not consistant. A column is exported (when I export underlying data) in one visualization, but is not exported when I do the same on another visualization. (The column is not used in either visualization)
I read another user's question - almost identical http://community.powerbi.com/t5/Service/Export-underlying-data/m-p/107413#M17471 - and the suggestion was to make that field a text field. Is that true? That seems to be an unreasonable restriction. The fields in my table are numerics/dates/text - and I really can't change them (because those are used for other calculations/filters).
Is there any way to export "All" columns in the table when we export underlying data? (Similar to how an Excel pivot table exports all the source data when a number is double clicked)
Currently, only columns which are used to create the visual can be exported on Power BI Desktop, while exporting data on Power BI service can export the columns which are used to create the visual together with all “Text” type columns.
So I would suggest you submit your requirement on Power BI Ideas to improve Power BI on this feature.